1. Field of the Invention
The invention relates to a method and apparatus for percutaneously implanting an aortic valve prosthesis.
2. Description of the Related Art
Typically, in the case of valvular heart diseases, valvular defects are repaired by a surgical valve implantation which requires thoracotomy and extracorporeal circulation, which may include placing the patient on a heart-lung machine. Such conventional surgical techniques to repair or replace valves, such as aortic valves, present problems for patients who cannot be operated on because of an associated disease or very old age, or present problems for patients who could be operated on, but only at a very high risk. For example, in the case of aortic stenosis, which is a disease of the aortic valve in the left ventricle of the heart, the only commonly available treatment is the replacement of the stenosed aortic valve by a prosthetic valve via surgery, which in the case of elderly patients presents the previously described disadvantages. In this regard, the use of the term diseased valve, or diseased aortic valve, is meant to include aortic valves in need of replacement and/or repair due to stenosis, disease, old age, or otherwise damaged valves, requiring replacement.
Recently, it has been proposed to replace, or implant, an aortic valve prostheses in the cardiac catheterization lab of a hospital, using a balloon catheter, or balloon dilatation catheter, to deliver and implant an aortic valve prosthesis within a diseased aortic valve. Thus, a more invasive chest surgery may be avoided. The aortic valve prosthesis is catheter delivered through the aorta. An example of such a technique and apparatus is described in United States Patent Application Publication No. U.S. 2003/0109924, published Jun. 12, 2003.
A major disadvantage associated with the use of such a technique is that when the new aortic valve prosthesis is being deployed within the diseased aortic valve, the patient will have a period of loss of all blood flow during the period of time that the aortic valve prosthesis is being implanted. In the case of the foregoing described technique and aortic valve prosthesis, a balloon expandable stent is included as a part of the aortic valve prosthesis. Upon the expansion of the stent by an expandable balloon associated with the catheter, the expanded balloon occludes the orifice of the aorta for a period of time while the new aortic valve prosthesis is being deployed, or implanted. The period of time may vary depending upon how easy or how difficult it is to implant the new aortic valve prosthesis. Because of this serious disadvantage, the time taken to implant such an aortic valve prosthesis must be kept to a minimum, which in turn may affect the success of the implantation of the aortic valve prosthesis securely within the diseased aortic valve, or may affect the positioning of the aortic valve prosthesis in an optimal position within the diseased aortic valve.
Accordingly, prior to the development of the present invention, there has been no method and apparatus for implanting an aortic valve prosthesis which: may be readily performed percutaneously without chest surgery and without complete loss of blood flow from the heart to the patient's body; and can be transluminally implanted in a cardiac catheterization lab setting with minimal blood loss and relatively low risk of morbidity and mortality. Therefore, the art has sought a method and apparatus for implanting an aortic valve prosthesis which may be readily performed percutaneously without chest surgery, and without complete loss of blood flow from the heart to the patient's body; may be transluminally implanted; and may be implanted in a cardiac catheterization lab setting by a cardiologist with minimal blood loss and relatively low risk of morbidity and mortality.